The present invention relates to communication devices. More particularly, it relates to a communication device having a transmitter and/or a receiver.
Communication devices of this type are known in the art and used in many varieties. It is believed that the existing communication devices can be further improved.
Accordingly, it is an object of the present invention to provide a communication device which is a further improvement of the existing devices.
In keeping with these objects and with others which will become apparent herein after, one feature of the present invention resides, briefly stated, in a communication device which has at least one element selected from the group consisting of a transmitter, a receiver, and both; an energy storage; a signal coupling connecting said at least one element with said energy storage for transmitting and/or receiving a radio signal.
With the communication device it is designed in accordance with the present invention, it has an advantage in that no separate antenna is needed for reception or transmission of radio signals.
In the present invention, advantageously an available energy storage is utilized as an antenna. Thereby this available element is used to perform an additional function. For this purpose a signal coupling from the transmitter or the receiver to the energy storage is provided.
In particular for miniature applications, where space conditions do not provide a possibility for an optimal antenna guide, it is advantageous to use as the antenna mechanical conducting elements which lead away from the circuitry such as the battery or another energy storage. Naturally, several batteries or a whole battery pack can be utilized as well.
In accordance with the present invention it is especially advantageous when a first pole of the battery or the accumulator serves for a signal coupling. Therefore this first pole is connected for example to ground through an inductivity, so that this battery pole is placed with high frequency above ground. This is the case when the outer housing of the battery acts as the ground. Since an inductivity exhibits a higher resistance with an increasing frequency, therefore with high frequency signals which must be transmitted, almost a separation to ground is made available. The second pole, to the contrary, can be also connected through an inductivity. This depends on the presumptions of the actual design, such as for example the dimensions, the used frequency and the wave resistors.
It is further advantageous when the energy storage element itself is a magnetic loop antenna which is especially suitable for the compact construction. Such a magnetic loop has for example a variable condensor, for equalization of the loop antenna. Such an antenna has conventionally a higher quality factor and makes possible a selective reception or a selective transmission.
Moreover, its advantageous when in accordance with the present invention all elements of the communication device are accommodated in one housing composed, for example, of a synthetic plastic material, or in other words produced from a non-conductive material.
The inventive communication device advantageously can be utilized also as a short-circuiting device, for example as a door or an alarm contact, as a motion detector, as a fire detector, as a temperature detector or also in other areas in household and security technologies.
The novel features which are considered as characteristic for the present invention are set forth in particular in the appended claims. The invention itself, however, both as to its construction and its method of operation, together with additional objects and advantages thereof, will be best understood from the following description of specific embodiments when read in connection with the accompanying drawings.